EP3633264B1

EP3633264B1 - Optical unit

Info

Publication number: EP3633264B1
Application number: EP18805800.2A
Authority: EP
Inventors: Satoshi Yamamura
Original assignee: Koito Manufacturing Co Ltd
Current assignee: Koito Manufacturing Co Ltd
Priority date: 2017-05-26
Filing date: 2018-05-08
Publication date: 2023-01-18
Anticipated expiration: 2038-05-08
Also published as: US11353188B2; US20200080702A1; EP3633264A4; JPWO2018216456A1; WO2018216456A1; EP3633264A1; JP7009465B2; CN110621930A

Description

[TECHNICAL FIELD]

The present invention relates to an optical unit for use in a vehicle lamp.

[BACKGROUND ART]

In an optical unit devised to date, light emitted sideways from a light source is reflected forward by a rotary reflector to form a desired light-distribution pattern (see patent document 1).

[patent document 1] WO2011/129105
[patent document 2] DE102014211678 A1 discloses an optical unit with a reflector surface whose axis of rotation is oblique to the optical axis.

[PROBLEM TO BE SOLVED BY THE INVENTION]

The aforementioned optical units tend to have a large width as a whole since the light source is disposed toward a side of the rotary reflector. Therefore, it may be difficult to employ such an optical unit in a vehicle headlamp due to a design constraint.
The present invention has been made in view of the above and is directed to providing, for example, an optical unit with a novel configuration arrangement.

[MEANS TO SOLVE THE PROBLEM]

To solve the above-described problem, an optical unit according to the present invention is an optical unit for use in a vehicle lamp as defined in claim 1.The optical unit includes a light source and a rotary reflector that rotates about an axis of rotation while reflecting light emitted from the light source. The rotary reflector is disposed such that the axis of rotation of the rotary reflector intersects a horizontal plane.
According to the invention the light source is disposed below the axis of rotation of the rotary reflector.
The optical unit further includes a projection lens that projects the light emitted from the light source and reflected by the rotary reflector in a light-irradiation direction of the optical unit. The light source is disposed between the rotary reflector and the projection lens in a front-back direction of a vehicle and below the axis of rotation of the rotary reflector. This configuration can limit the length of the optical unit in the front-back direction of the vehicle.
The light source includes a first light source including one or more first light-emitting elements and a second light source including one or more second light-emitting elements. The rotary reflector reflects light emitted from the first light source off one region in a right or left side of the rotary reflector and reflect light emitted from the second light source off another region in the right or left side of the rotary reflector. This configuration allows the single rotary reflector to reflect the light emitted from the two light sources.
The optical unit further includes a substrate on which the first light source and the second light source are mounted. This configuration can reduce the number of components and reduce the manufacturing processes.
The projection lens may include a first projecting portion where the light emitted from the first light source and reflected by the rotary reflector enters and a second projecting portion where the light emitted from the second light source and reflected by the rotary reflector enters. This configuration can form a plurality of light-distribution patterns.
A light-blocking portion may be provided on an incident surface of the projection lens, and the light-blocking portion may be disposed to prevent the light emitted from the first light source and reflected by the rotary reflector from entering the second projecting portion and to prevent the light emitted from the second light source and reflected by the rotary reflector from entering the first projecting portion. This configuration can suppress, for example, a situation in which, although the second light source is off, the light emitted from the first light source passes through the second projecting portion as stray light to produce glare. Alternatively, the above configuration can suppress a situation in which, although the first light source is off, the light emitted from the second light source passes through the first projecting portion as stray light to produce glare.
The first projecting portion may have a posterior focal length L1 greater than a posterior focal length L2 of the second projecting portion. The axis of rotation of the rotary reflector may be inclined toward the first projecting portion relative to the front-back direction of the vehicle. This configuration allows the light emitted from the first projecting portion to be condensed more easily than the light emitted from the second projecting portion, for example. To rephrase, the light emitted from the second projecting portion is diffused more easily than the light emitted from the first projecting portion.
The rotary reflector may include a rotary portion and a plurality of blades that are provided around the rotary portion and that function as a reflective surface. The reflective surface of the rotary reflector may be provided such that light from the light source reflected by the rotating reflective surface forms a light-distribution pattern.
Any optional combination of the above constituent elements or an embodiment obtained by converting what is expressed by the present invention among a method, an apparatus, a system, and so on is also effective as an embodiment of the present invention.

[ADVANTAGE OF THE PRESENT INVENTION]

The present invention can provide an optical unit with a novel configuration arrangement.

[BRIEF DESCRIPTION OF THE DRAWINGS]

Fig. 1 is a top view schematically illustrating a general configuration of a vehicle headlamp according to a first embodiment which does not form part of the present invention;
Fig. 2 is a side view schematically illustrating a general configuration of the vehicle headlamp according to the first embodiment;
Fig. 3 is a side view schematically illustrating a configuration of a rotary reflector according to the first embodiment;
Fig. 4 is a top view schematically illustrating a configuration of the rotary reflector according to the first embodiment;
Fig. 5(a) is a schematic diagram for describing a light source image obtained when the rotary reflector's blade is being rotated 20° relative to a reference position, and Fig. 5(b) is a schematic diagram for describing a light source image obtained when the rotary reflector's blade is being rotated 160° relative to the reference position;
Fig. 6 is a top view illustrating a general configuration of a vehicle headlamp according to a second embodiment according to the invention;
Fig. 7 is a top view schematically illustrating a general configuration of a vehicle headlamp according to a third embodiment according to the present invention;
Fig. 8 is a side view schematically illustrating a general configuration of the vehicle headlamp according to the third embodiment;
Fig. 9 is a top view schematically illustrating a general configuration of a vehicle headlamp according to a fourth embodiment according to the present invention; and
Fig. 10 is a side view schematically illustrating a general configuration of the vehicle headlamp according to the fourth embodiment.

[MODE FOR CARRYING OUT THE INVENTION]

Hereinafter, the present invention will be described on the basis of embodiments with reference to the drawings. Identical or equivalent constituent elements, members, and processes illustrated in the drawings are given identical reference characters, and duplicate descriptions thereof will be omitted as appropriate. The embodiments are illustrative in nature and are not intended to limit the invention. Not all the features and combinations thereof described in the embodiments are necessarily essential to the invention.
An optical unit according to the embodiments can find its use in a variety of lamps . In the cases described hereinafter, the optical unit according to the embodiments is applied to, among lamps, a vehicle headlamp.

[First Embodiment]

Fig. 1 is a top view schematically illustrating a general configuration of a vehicle headlamp according to a first embodiment which does not form part of the present invention.
Fig. 2 is a side view schematically illustrating a general configuration of the vehicle headlamp according to the first embodiment. In the following drawings, some components, such as a lamp body, a cover, and an extension, constituting the vehicle headlamp are omitted.
A vehicle headlamp 10 includes an optical unit 12. The optical unit 12 includes a light source 14 and a rotary reflector 16 that rotates about an axis of rotation R while reflecting light emitted from the light source 14. The rotary reflector 16 is disposed such that the axis of rotation R of the rotary reflector intersects a horizontal plane H.
Herein, the horizontal plane H can be defined not only physically as a plane intersecting the earth's gravitational force at a right angle but also, for example, as a plane that includes an optical axis and/or a center axis of a projection lens described later (a straight line passing through the center of the projection lens) and that is parallel to a reference surface P on which the vehicle headlamp 10 is placed. Alternatively, the horizontal plane H may be a plane that includes the optical axes of the vehicle's right and left headlamps. That the axis of rotation R intersects the horizontal plane H includes a case in which a line extending from the axis of rotation R intersects the horizontal plane H.
The light source 14 includes four light-emitting elements 14a arrayed in a widthwise direction W of the vehicle. The light-emitting elements are each a semiconductor light-emitting element, such as an LED, an EL element, or an LD element. The light-emitting elements 14a are mounted on a single element-mounting substrate 15. The element-mounting substrate 15 is fixed to a surface of a heat sink 17.
Fig. 3 is a side view schematically illustrating a configuration of the rotary reflector according to the first embodiment which does not form part of the present invention. Fig. 4 is a top view schematically illustrating a configuration of the rotary reflector according to the first embodiment.
The rotary reflector 16 rotates with a driving source, such as a motor, unidirectionally about the axis of rotation R. The rotary reflector 16 includes blades 16a, serving as a reflective surface, provided to form a desired light-distribution pattern by scanning light from each light source reflected by the rotating rotary reflector 16. In other words, the rotating operation of the rotary reflector 16 causes visible light from a light emitter to be emitted as an irradiation beam, and a desired light-distribution pattern is formed as the rotary reflector 16 scans the irradiation beam.
The rotary reflector 16 includes the two blades 16a, which function as a reflective surface and are identical in shape, and the two blades 16a are provided around a cylindrical rotary portion 16b. The axis of rotation R of the rotary reflector 16 is at an angle relative to the horizontal plane H. To rephrase, the axis of rotation R intersects a scanning plane S of light (irradiation beam) from each light source that scans in the right-left direction through rotation. This configuration reduces the thickness of the optical unit. Herein, the scanning plane can be regarded as a fan-shaped plane formed by continuously connecting the trajectories of light from each light source, or the scanning light, for example. This scanning plane S may be regarded as the horizontal plane H described above.
Each blade 16a of the rotary reflector 16 has a twisted shape in which the angle formed by an optical axis Ax and the reflective surface changes along the circumferential direction about the axis of rotation R. This configuration enables the scan with the light from the light source 14, as illustrated in Fig. 4.
As illustrated in Fig. 2, in the optical unit 12 according to the present embodiment, the light source 14 can be disposed below the axis of rotation R of the rotary reflector 16. Alternatively, as the optical unit 12 is inverted vertically, the light source 14 can be disposed above the axis of rotation R of the rotary reflector 16.
The optical unit 12 further includes a projection lens 18 that projects the light emitted from the light source 14 and reflected by the rotary reflector 16 in a light-irradiation direction (forward F) of the optical unit 12. The light source 14 is disposed between the rotary reflector 16 and the projection lens 18 in the front-back direction of the vehicle (the direction along the optical axis Ax) and below an optical path L of the light reflected by the rotary reflector 16 (or below the axis of rotation of the rotary reflector 16). This configuration can limit the length of the optical unit 12 in the front-back direction of the vehicle.
The optical unit 12 according to the present embodiment includes a condenser lens 20 serving as a primary optical system (optical member) that redirects the optical path of the light emitted from the light source 14 toward the blades 16a of the rotary reflector 16.
Now, movement of a light source image in association with rotation of the rotary reflector 16 will be described. Fig. 5 (a) is a schematic diagram for describing a light source image obtained when a blade 16a of the rotary reflector 16 is being rotated 20° relative to a reference position. Fig. 5(b) is a schematic diagram for describing a light source image obtained when a blade 16a of the rotary reflector 16 is being rotated 160° relative to the reference position.
As illustrated in Fig. 5 (a), a secondary light source (light source virtual image) 19 of the light source 14 is on the opposite side from the light source 14 across the blade 16a. Then, as light from the secondary light source 19 is projected in an inverted manner, a pattern P1 composed of a light source image is formed on the front side. Thereafter, as illustrated in Fig. 5(b), the blade 16a of the rotary reflector 16 rotates to the 160-degree position relative to the reference position. The secondary light source (light source virtual image) 19 of the light source 14 obtained at this position is illustrated in Fig. 5(b). Then, as light from the secondary light source 19 is projected in an inverted manner, a pattern P1 composed of a light source image is formed on the front side.
As illustrated in Figs. 5(a) and 5(b), the rotary reflector 16 includes the blades 16a that function as a reflective surface. The reflective surface of the rotary reflector 16 is provided such that light from the light source reflected by the rotating rotary reflector 16 forms a light-distribution pattern.

[Second Embodiment]

Fig. 6 is a top view illustrating a general configuration of a vehicle headlamp according to a second embodiment according to the present invention. A side view illustrating a general configuration of the vehicle headlamp according to the second embodiment is substantially the same as the side view illustrated in Fig. 2, and thus the drawing is omitted.
A vehicle headlamp 30 includes an optical unit 32. The optical unit 32 includes a first light source 34 including four light-emitting elements 34a and a second light source 36 including three light-emitting elements 36a. The rotary reflector 16 reflects light emitted from the first light source 34 off a region R1 in the right side of the rotary reflector and reflects light emitted from the second light source 36 off a region R2 in the left side of the rotary reflector 16. This configuration allows the single rotary reflector 16 to reflect the light emitted from the two light sources.
The optical unit 32 further includes a common element-mounting substrate 38 on which the first light source 34 and the second light source 36 are mounted. This configuration can reduce the number of substrates and reduce the manufacturing processes. The element-mounting substrate 38 is fixed to a surface of a heat sink 39.
The optical unit 32 further includes a projection lens 40. The projection lens 40 includes a first projecting portion 40a where light emitted from the first light source 34 and reflected by the rotary reflector 16 enters and a second projecting portion 40b where light emitted from the second light source 36 and reflected by the rotary reflector 16 enters. The projection lens 40 is a unitary component in which the first projecting portion 40a and the second projecting portion 40b are integrated. This configuration can reduce the number of lenses. This configuration also allows a single light-distribution pattern where a plurality of light-distribution patterns are combined to be formed with a single optical unit.
The optical unit 32 according to the present embodiment includes a condenser lens 42, serving as a primary optical system (optical member), that redirects the optical path of the light emitted from the first light source 34 toward the region R1 in the right side of the rotary reflector 16 and a condenser lens 44, serving as a primary optical system (optical member), that redirects the optical path of the light emitted from the second light source 36 toward the region R2 in the left side of the rotary reflector 16.

[Third Embodiment]

Fig. 7 is a top view schematically illustrating a general configuration of a vehicle headlamp according to a third embodiment according to the present invention. Fig. 8 is a side view schematically illustrating a general configuration of the vehicle headlamp according to the third embodiment. Configurations similar to those in the second embodiment are given identical reference characters, and descriptions thereof will be omitted as appropriate.
A vehicle headlamp 50 according to the third embodiment includes an optical unit 52. The optical unit 52 includes a projection lens 54. A first projecting portion 54a of the projection lens 54 has a posterior focal length L1 (the distance between a principal point H and a posterior focal point F) greater than a posterior focal length L2 (the distance between a principal point H' and a posterior focal point F') of a second projecting portion 54b. The axis of rotation R of the rotary reflector 16 is inclined toward the first projecting portion 54a relative to the front-back direction of the vehicle (the direction along the optical axis Ax).
This configuration allows light emitted from the first projecting portion 54a to be condensed more easily than light emitted from the second proj ecting portion 54b, for example . To rephrase, the light emitted from the second projecting portion 54b is diffused more easily than the light emitted from the first projecting portion 54a. To further rephrase, the light that has passed through the first projecting portion 54a has a relatively smaller scanning region, which in turn leads to a higher luminous intensity. Meanwhile, the light that has passed through the second projecting portion 54b has a relatively greater scanning region, which in turn leads to a lower luminous intensity.
In other words, a light-distribution pattern formed by the light that has passed through the first projecting portion 54a has a small irradiation range but a high luminous intensity and is thus suitable for a high-beam light-distribution pattern, for example. A light-distribution pattern formed by the light that has passed through the second projecting portion 54b has a low luminous intensity but a great irradiation range and is thus suitable for a low-beam light-distribution pattern, for example.

[Fourth Embodiment]

Fig. 9 is a top view schematically illustrating a general configuration of a vehicle headlamp according to a fourth embodiment according to the present invention. Fig. 10 is a side view schematically illustrating a general configuration of the vehicle headlamp according to the fourth embodiment. Configurations similar to those in the foregoing embodiments are given identical reference characters, and descriptions thereof will be omitted as appropriate.
A vehicle headlamp 60 according to the fourth embodiment includes an optical unit 62. The optical unit 62 includes a projection lens 46 having two convex lens portions on an incident side and one convex lens portion on an exit side. A light-blocking portion 64 is provided on an incident surface 46c of the projection lens 46. The light-blocking portion 64 is disposed to prevent light emitted from the first light source 34 and reflected by the rotary reflector 16 from entering a second projecting portion 46b and to prevent light emitted from the second light source 36 and reflected by the rotary reflector 16 from entering a first projecting portion 46a.
The light-blocking portion 64 is a plate-like member and is disposed in a plane that includes a boundary 46d between the first proj ecting portion 46a and the second projecting portion 46b of the projection lens 46 and disposed behind the boundary 46d. This configuration can suppress, for example, a situation in which, although the second light source 36 is off, the light emitted from the first light source 34 passes through the second projecting portion 46b as stray light to produce glare. Alternatively, the above configuration can suppress a situation in which, although the first light source 34 is off, the light emitted from the second light source 36 passes through the first projecting portion 46a as stray light to produce glare.

(Variations)

Now, examples of the specification range of each configuration of the optical unit will be provided. An angle α (see Fig. 2) formed by the axis of rotation R of the rotary reflector 16 and the horizontal plane H is, for example, in a range of from 1° to 45°, preferably in a range of from 3° to 30°, or more preferably in a range of from 5° to 20°. The diameter of the rotary reflector 16 is, for example, in a range of from 30 mm to 100 mm, preferably in a range of from 40 mm to 80 mm, or more preferably in a range of from 50 mm to 70 mm.
The width (in the widthwise direction of the vehicle) of the projection lens is, for example, in a range of from 50 mm to 120 mm, preferably in a range of from 60 mm to 100 mm, or more preferably in a range of from 70 mm to 90 mm. The height (in the heightwise direction of the vehicle) of the projection lens is, for example, from 20 mm to 60 mm, preferably from 25 mm to 50 mm, or more preferably from 25 mm to 35 mm.
An angle β of incidence (see Fig. 2) at which light emitted from the light source is incident on the blades 16a of the rotary reflector is less than 45°, preferably no more than 30°, or more preferably no more than 20°. This configuration improves the efficiency with which the light flux reflected by the rotary reflector is incident on the projection lens.
Thus far, the present invention has been described with reference to the foregoing embodiments. The present invention, however, is not limited to the foregoing embodiments.

[DESCRIPTION OF THE REFERENCE NUMERALS]

10 vehicle headlamp, 12 optical unit, 14 light source, 14a light-emitting element, 15 element-mounting substrate, 16 rotary reflector, 16a blade, 16b rotary portion, 18 projection lens, 30 vehicle headlamp, 32 optical unit, 34 first light source, 34a light-emitting element, 36 second light source, 36a light-emitting element, 38 element-mounting substrate, 40 projection lens, 40a first projecting portion, 40b second projecting portion, 46c incident surface, 64 light-blocking portion

[INDUSTRIAL APPLICABILITY]

The present invention can find its use in vehicle lamps.

Claims

An optical unit (12) for use in a vehicle lamp, the optical unit comprising:
a light source (14); and

a rotary reflector (16) structured to rotate about an axis of rotation while reflecting light emitted from the light source (14),

wherein the rotary reflector (16) is disposed such that the axis of rotation of the rotary reflector (16) intersects a horizontal plane

a projection lens (18) for projecting the light emitted from the light source (14) and reflected by the rotary reflector (16) in a light-irradiation direction of the optical unit (12),

wherein the light source (14) is disposed between the rotary reflector (16) and the projection lens (18) in a front-back direction of a vehicle and below the axis of rotation of the rotary reflector (16), wherein the light source includes a first light source (34) including one or more first light-emitting elements (34a) and a second light source (36) including one or more second light-emitting elements (36a), and

the rotary reflector (16) is structured to reflect light emitted from the first light source (34) off one region (R1) in a right or left side of the rotary reflector and to reflect light emitted from the second light source (36) off another region (R2) in the right or left side of the rotary reflector, wherein the optical unit (32) further comprises

a substrate (38) on which the first light source (34) and the second light source (36) are mounted.
The optical unit (32) according to claim 1, wherein
the projection lens (40) includes a first projecting portion (40a) where the light emitted from the first light source (34) and reflected by the rotary reflector enters and a second projecting portion (40b) where the light emitted from the second light source (36) and reflected by the rotary reflector enters.
The optical unit (62) according to claim 2, wherein
a light-blocking portion (64) is provided on an incident surface (46c) of the projection lens (46), and

the light-blocking portion (64) is disposed to prevent the light emitted from the first light source (34) and reflected by the rotary reflector (16) from entering the second projecting portion (46b) and to prevent the light emitted from the second light source (36) and reflected by the rotary reflector (16) from entering the first projecting portion (46a).
The optical unit (62) according to claim 2 or 3, wherein
the first projecting portion (46a) has a posterior focal length L1 greater than a posterior focal length L2 of the second projecting portion (46b), and

the axis of rotation of the rotary reflector (16) is inclined toward the first projecting portion (46a) relative to the front-back direction of the vehicle.
The optical unit (12) according to any one of claims 1 to 4, wherein
the rotary reflector (16) includes
a rotary portion (16a), and

a plurality of blades (16b) that are provided around the rotary portion and that function as a reflective surface, and

the reflective surface is provided such that light from the light source (14) reflected by the rotating reflective surface forms a light-distribution pattern.